Solari A J, Fechheimer N S
Department of Dairy Science, Ohio State University, Columbus 43210.
Genome. 1988 Dec;30(6):900-2. doi: 10.1139/g88-145.
Synaptonemal complex analysis of an exceptional tetraploid oocyte from a diploid chicken heterozygous for the MN t (Z;1) rearrangement was performed by electron microscopy of a spread preparation. Ten separate quadrivalents (26% of the chromosomal axes) were analyzed, as well as 50 autosomal bivalents. All the axes less than 2.5 microns in length formed bivalents (38) only, while axes in the 2.5-4.2 micron range formed 5 quadrivalents and 12 bivalents. The longer, separate axes formed quadrivalents only. Partner switches in excess of one were documented. The two identical W chromosomes paired only at the ends of their short arms. Quadrivalent formation may require a threshold length (2.5 microns), at least in this species. The tip of the short arm of the W chromosome may be a pairing initiation point, and it corresponds to the region associated with a localized recombination nodule previously described in diploid oocytes.
通过铺展制片的电子显微镜技术，对一只因MN t (Z;1)重排而杂合的二倍体鸡所产生的异常四倍体卵母细胞进行了联会复合体分析。分析了10个单独的四价体（占染色体轴的26%）以及50个常染色体二价体。所有长度小于2.5微米的轴仅形成二价体（38个），而长度在2.5 - 4.2微米范围内的轴形成了5个四价体和12个二价体。较长的单独轴仅形成四价体。记录到了超过一个的配对交换。两条相同的W染色体仅在其短臂末端配对。至少在这个物种中，四价体的形成可能需要一个阈值长度（2.5微米）。W染色体短臂末端可能是配对起始点，并且它对应于先前在二倍体卵母细胞中描述的与局部重组结节相关的区域。
